Justin Slaughter
The pension also committed to the asset manager's previous fund, which closed on its $1bn target.
The firm tapped its $2.8bn energy mezzanine fund for deal with EOG Resources.
The Los Angeles-based firm has invested $1.8bn in direct originations since 2005.
The fund targets underperforming firms still generating cash, mostly in Europe.
The debt portfolio had a total return of 13.9% the year ending 31 March.
NS Investment stock will be converted into cash and shares of TCG BDC.
The New York Life Insurance subsidiary surpassed its previous $1bn mezz fund.
The Texas-based asset manager closed its previous vehicle on $361m last year.
The predecessor fund closed on $1.3bn in 2014.
NMERB has previously committed a total of $90m to Stonepeak funds.